So, in this sense i don't have any problems to criticise things in China.
My pessimism is this one: (Maybe you know this one) A high-rating chinese philosopher told me that he knew the daughter of Deng Xiaoping. And she told him that when Deng Xiaoping was dying, some high functionaries visited him and asked him (to kiss his ass, of course) "What was the greatest thing you did?".
They thought, the answer will be "opening up reforms" and so on; but he said "That i resisted the temptation to go all the way and liberalise politics also".
The tragedy is that - it's horrible - i'm not glad to say this, but what if he was right.
I think that at that point, after Tiananmen, or before, to simply opt for political pluralism - i think it wouldn't end well.

What does this mean?

I don't believe in this naive liberal vision. So what should we do? Should China be our model?
No, absolutely not.
But what do we have as an alternative?
So, yes, i will always sign protests for those in Hongkong, although of course, i was shocked when some of them then called "Trump, save us from China" and so on.